publicinterface Map<K,V>{/** Retrieves the value associated with this key, or null if not found. */public V get(K key);/** Assigns a value to be associated with the given key. * If the key is not already in the map, it gets added. * Otherwise, if it's already in the map, its associated value is modified. */publicvoid set(K key, V value);/** Returns the number of distinct keys in this map. */publicint size();}